You should always have the contractor call the locates in! You don't want to take the responsibility of someone hitting a gas, hydro, cable or bell line. The contractor is responsible if they are drilling your holes on your property.
Don't let them talk you into calling the locates in yourself. No, the responsibility is the contractor who is drilling your holes.
They are able to ask for a priority and often locates can be obtained in 3 working days. Sometimes during peak season it may take up to 5 working days.
You do not have to be home, the locators come and mark if you have any utilities in the area. The will fax or send an e-mail to the contractor.